Data Storage Unit Converter

What Is the Data Storage Unit Converter?

Storage units come in two competing systems that get commonly conflated: the decimal system (KB/MB/GB/TB, based on powers of 1000, used by hard drive manufacturers and most marketing) and the binary system (KiB/MiB/GiB/TiB, based on powers of 1024, used by operating systems reporting actual memory/file sizes). This tool converts between any combination of both.

How to Use This Tool

Enter a value and choose source and target units from either system. The converted value appears instantly.

Why "1TB" Drives Show as Less in Your OS

Practical Uses

• Understanding why a storage device's marketed size doesn't match what your OS reports
• Converting between file-size units for accurate capacity planning
• Explaining the KB-vs-KiB distinction precisely rather than approximately

For a byte count derived from actual text content, see the Text Byte Size Calculator.

A Worked Example

Suppose you buy a drive advertised as 500 GB. In decimal terms that is 500 x 1,000,000,000 = 500,000,000,000 bytes. To express that in the binary unit your operating system may use, divide by 1,073,741,824 (1024 cubed). The result is about 465.66 GiB. Nothing is missing from the drive: the same bytes are being counted with a larger unit. The gap between the two systems is about 2.4 percent at the kilo level, about 4.9 percent at giga, and about 10 percent at tera, so it grows as capacities increase.

Units the Tool Supports

• Bytes (B).
• Decimal: KB (1,000 bytes), MB, GB, TB, each a factor of 1,000 larger than the previous one.
• Binary: KiB (1,024 bytes), MiB, GiB, TiB, each a factor of 1,024 larger.

Bits, petabytes, and larger units are not offered, so convert those elsewhere or multiply by hand first. Also note that a lowercase b usually means bits in network speeds, and this tool does not handle bits.

Practical Tips for Accurate Results

• Match the unit to the source. Internet plans, drive packaging, and most phone storage specs use decimal units. Windows Explorer traditionally labels values with KB, MB, and GB but computes them in 1024-based math, while some other operating systems and tools report decimal.
• Convert both ways when comparing. To check if a 4 GB file fits on a device advertising 4 GB, make sure you compare decimal to decimal or binary to binary, since 4 GiB is larger than 4 GB.
• Keep enough digits. Long results are useful when you need exact byte counts, so do not round to the nearest whole number before the final step.

Common Mistakes

• Treating KB and KiB as interchangeable in a spreadsheet or script. A capacity calculation that uses 1000 in one place and 1024 in another will slowly drift off.
• Expecting formatted storage to equal the drive's raw size. The file system, formatting, and reserved system areas also use some of the capacity, so the free space you see will be lower than either figure this tool shows.
• Entering negative values or leaving the field blank and reading the previous result as current.

Where It Helps

It is handy for backup planning, comparing cloud storage quotas with local disks, explaining a support ticket about missing space, and writing documentation that states sizes unambiguously. If you need the byte size of some text rather than a unit conversion, use the Text Byte Size Calculator linked above.

Frequently Asked Questions